Hi Duy, On Wed, 3 May 2017, Nguyễn Thái Ngọc Duy wrote: > This code uses the result FILE pointer right away without the NULL > check. Let's use xfopen() and die if we could not open the file. That's > still better than crashing, > > Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@xxxxxxxxx> While funny to read, maybe it would be better to spell it out clearly: copy_alternates() called fopen() without handling errors. By switching to xfopen(), this bug is fixed. Ciao, Dscho